Apparatus for treating material



March 17, 1964 p w|| s 3,125,305

APPARATUS FOR TREATING MATERIAL Filed April 21, 1958 4 Sheets-Sheet 1 INVENTOR.

V Frof.1ng.|eler willems BY March 17, 1964 P.W1LLEMS 3,125,305

APPARATUS FOR TREATING MATERIAL Filed April 21, 1958 4 Sheets-Sheet 2 IN VEN TOR.

Frof.lng.le1er willems BY 4 Sheets-Sheet 3 Filed April 21, 1958 March 17, 1964 P. WILLEMS r 3,125,305

' APPARATUS FOR TREATING MATERIAL Fiied April 21, 1958 4 Sheets-Sheet 4 INVEINTORL 98 ProiJngfelcrWfllems United States Patent 3,125,305 APPARATUS FOR TREATING MATERIAL Peter Willems, Steinhofhalde 2022, Lucerne, Switzerland Filed Apr. 21, 1958, Ser. No. 729,694 Claims priority, application Switzerland Apr. 30, 1957 11 Claims. (Cl. 241-261) The invention relates to an apparatus for treating materials and mixtures of different materials continuously or in batches for purposes such as the digesting, pulping, mixing, dissolving, comminuting, and homogenizing of such materials and/or material mixtures by tearing, breaking, or comminuting them so as to increase their specific surface for performing or accelerating chemical processes.

Known apparatus for such purposes consists of a conical rotor which rotates in a hollow conical stator. The material to be treated is led through the annular space formed by the conical rotor and stator. The material is acted upon in this space by rotor and stator ribs extending along generating lines of the rotor and stator cones. This apparatus has the disadvantage that the rotor ribs throw the material from the gaps between them radially into the gaps between the stator ribs which are disposed on a conical surface of greater effective diameter than the rotor ribs, so that at least a large portion of the material escapes in an untreated condition through the stator gaps.

The invention overcomes these shortcomings. The material or material mixture is fed into a gap where it is subjected to the effect of cooperating elements which are arranged side by side transversely of the main direction of material movement.

With increasing diameter of the gap, the material to be treated may be subjected to mechanical stresses by forces rhythmically applied at adjustable high frequencies such as to impulses, shearing, crushing, squeezing, pulsations, pressure differences, cavitation and to secondary phenomena caused by these stresses. The frequency of the physical effects can be adjusted through the range of audible frequencies and up to high ultrasonics.

The invention may, for instance, be used for treating materials of any consistency, individual compounds or mixtures, in the solid, fibrous, thixotropic, Viscous, powdery, liquid and gaseous state. This treatment may, for instance, involve the digesting, pulping, disintegrating, dissolving, grinding, comminuting and/or homogenizing of the material, or the preparation of colloidal and stable suspensions and emulsions of any kind. The method according to the invention is particularly useful in the manufacture of cellulose, for reducing shives, fibre swelling, fibrillation and complete fibre separation. The method may also be used for initiating and enhancing chemical transformations, such as reduction, oxydation, addition, substitution, polymerisation, depolymerisation, sulphonation, alkylation, condensation, and saponification reactions for manufacturing washing and wetting agents, soapstocks etc.

The invention is also concerned with an apparatus having at least two coaxially arranged members, at least one of the members being rotatable relative to the other.

The members form a gap between them and have cooperating elements projecting into the gap in such a way that, in a direction transverse to the main direction of ice material movement through the gap, adjacent elements lie side by side.

One or several stages may be arranged before or after the gap in the direction of material flow in order to allow treatment of the material at any desired frequency with forces of desired intensity to ensure best quality of the final product.

Other objects and features of the novel apparatus will be apparent as the description proceeds, reference being had to the drawings, wherein FIG. 1 is a sectional elevation of a first embodiment of the invention, the section being taken along the line I-I of FIG. 2.

FIG. 2 is a top view, partly in section, along the line IIII of FIG. 1;

FIGS. 3 and 4 are sectional elevations through respecfive parts of two other examples of embodiments of the 1nvent1on;

FIG. 5 is an elevation, partly in section, of a further embodiment;

FIG. 6 is a sectional elevation through another example;

FIG. 7 is a section along the line X-X of FIG. 6, part of the casing being broken away; and

FIGS. 8 and 9 are sectional elevations of respective examples of applications of the apparatus according to the invention.

Referring now to FIGS. 1 and 2, a rotor disk 111 mounted on a driveshaft is surrounded by a stator casing 112 fixed to the underside of a container 113 and partly forming the bottom of the latter. The rotor shaft 110 is journalled in a bearing 114 of the stator casing 112. The rotor disk 111 carries prong-shaped beating rigid tearing elements 115 projecting into the container The end face 116 of the rotor disk 111 is concave. The shell 117 of the rotor disk 11 is a cone opening away from the container 113. A conical inner surface 118 of the stator casing 112 conforms to the cone 117 and forms together with the cone 117 a gap 119 whose width decreases from its inlet downward toward the outlet. The conical surface of the shell 117 carries five annular rows of rotor elements 120. Five annular rows of similar stator elements 121 integral with the conical surface 118 cooperate with the rotor elements 120. Adjacent cooperating rotor and stator elements 120 and 121 are arranged side by side in a direction transverse of the main direction of material movement or flow through the gap 119. As best seen in FIG. 2, the rotor elements 120 conform to the interstices between the stator elements 121, and vice versa when viewed in the direction of material movement so that the interstices are blocked only instantaneously during rotation of the rotor disk 111.

The stator casing 112 has an annular collector channel 122 containing at least one pump vane 123 mounted on the rotor disk 111. At its outlet 124 the collector channel 122 has a flange 125, to which a controlling valve (not shown) or a conduit (not shown) may be connected for discharging the treated material or stock or for returning it to the container 113. Elements 126 of the stator 112 cooperate with the tearing rotor elements 115 for tearing and reflecting action. The elements 126 are dimensioned and shaped so as to act simultaneously as baffles for directing the circulation of the substance to be treated, and to engage the prong-shaped elements 115.

A separator ring 127 fixed to the rotor 111 covers the inlet to the annular space of the gap 119 and has perforations 128 whose size may be chosen at will. As shown in FIG. 2, the perforations 128 are elongated in a radial direction. The separator ring 127 does not only prevent entry of insufliciently comminnted or decomposed material into the gap 119, but its radially extending portions 129 between the perforations 128 throw foreign bodies, such as metal pieces, needles etc. into the bottom of the container 113 where they may be caught in troughs, behind annular walls, by magnets etc. and discharged from the container.

The rotor and stator elements 121) and 121 of P163. 1 and 2, whose effect will be explained in connection with other examples of the inventive apparatus, are pyramidal in shape or teeth with trapezoidal flanks. The choice of the shape of the elements 123 and 121 depends on the desired effect, whether shearing, crushing, squeezing, friction, rebounding or pulsating action or a plurality of these phenomena or other effects are to be obtained by the cooperation of the elements, also whether heating of the material by friction is preferred.

The embodiment of FIG. 3 will now be described in so far as it is distinguished from the preceding example. The working gap 119 lying between the plane rotor disk 111 and the stator casing 112 extends approximately along a plane at a right angle to the axis of the shaft 110. Since the inner surface 118 of the stator 112 is a cone with a large apex angle, the gap 119 tapers somewhat towards the outside. The rotor disk 111 carries five annular rows of tooth-shaped elements 120 and the stator 112 carries four annular rows of elements 121 corresponding to the elements 120 and intermeshing with the rotor elements. The outermost element row of the stator 112 is a ring 135 having slot-shaped perforations 136. Rings of this kind have a particularly intense smashing and shearing effect. The perforations 136 of the ring 135 may have a radial position or deviate from the radial direction. For the choice of the most favorable cross section of the ring 135 the same considerations will apply as explained in the description of FIG. 1 for the choice of the cross section of the elements 120 and 121. The number and size of the perforations 136 for each ring 135 may be selected within the limits of manufacturing possibilities, so that the ring 135 may be a sieve. The physical effects in the apparatus such as shearing, crushing, rebounding, pulsation, pressure differences, cavitation etc., will thereby occur cyclically on the edges and the flanks of the perforations at extremely high frequencies. Simultaneously, the size of the particles of material produced is held within desired limits.

In the embodiment of FIG. 3 the separator ring 127 is conical.

The foreign bodies thrown towards the outside by the separator ring 127 are collected in a trough 137 of the container 113 and can be removed through a bottom gate 138.

In the embodiment of FIG. 4, a centrifugal screen 142 with sieve-like perforations is mounted on the rotor 111 and inserted in the path of flow from the gap 119 to a collector channel 143, the screen 142 separating the material into different components. The said centrifugal screen acts as a filter device which separates the material from liquid and/or from fine components. The annular screen 142 is coaxial with the axis of rotation and is conical. The material leaving the working gap 119 is thrown against the screen 142. Due to the centrifugal effect of the screen 142 and depending on the aperture size of its perforations, either only liquid or also finer particles of the material are passed through the screen 142. The centrifugal material is collected in the channel-shaped collector 143 mounted on the stator 112, the collector channel 143 having at least one drain 144 for the liquid or other constituents collected in it. A partition wall 145 fixed to the channel 143 is coaxial to and extends around the screen 142. The wall 145 serves for separating the material accumulated on the upper surface of the screen 142 and thrown beyond the upper edge of the screen 142 from the material passing through the screen 142 and for removing it through the drain 14-6 as soon as it surmounts the upper edge of the annular screen 142. Entrainment vanes 147 and 143 fixed to the rotor 111 ensure safe discharge of the material accumulated on the screen 142 and in the channel 143 through the drains 144 and 146 respectively.

In FIG. 4, the elements and 121 are arranged in a terraced or stepped manner and have triangular flanks. This shape of the elements corresponds in many cases to the centrifugal urge of the material towards the conical casing wall 118. The material flows through the working gap 119 along a zigzag line and is conveyed through the gap 119 in several stages approximately at a right angle to the edges or flanks of the elements. A terraced arrangement of the elements 120 and 121 can also be used in other embodiments of the apparatus according to the invention.

Referring now to the embodiment of FIG. 5, a twopart conical casing 1 forms the stator and has an intake 2 and an outlet 3. The two casing parts are bolted together along flanges 4. At the inlet, the inner wall of the casing 1 has stator ribs 5 extending along generating lines of the inner wall and having a rectangular cross section. Between every two adjacent stator ribs 5 are stator grooves or channels 6 extending in the main direction of movement of the material to be treated. The stator ribs 5 are followed in the direction of material movement "by three annular rows of teeth 7 integral with or fixed to the casing 1. Every row of teeth 7 has a greater number of teeth of smaller cross section than the preceding row in order to increase the frequency of power pulses acting on the material. After the rows of teeth 7 the casing 1 carries stator ribs 8 extending along generating lines of the conical inner casing wall. The grooves or channels 9 between adjacent ribs 8 extend in the main direction of material movement. The ribs 8 are followed by the last treatment stage in the form of four rows 10 of stator teeth. Every row It) has a greater number of teeth of smaller cross section than the preceding row 16 in order to increase the frequency of the power pulses acting on the material. A shaft 12 supported in bearings 11 of the casing 1 carries a drive pulley 13 and the conical hollow rotor 14. Within the range of opera tion of the stator ribs 5, the rotor 14 has rotor ribs 15 having a cross section similar to the stator ribs 5. The ribs 15 as well as the grooves or channels 16 between them extend along generating lines of the conical rotor surface, that is, along the main direction of material movement. Within the range of operation of the stator teeth 7, the rotor 14 carries three rows 17 of teeth, the rows 17 intermeshing with corresponding rows of stator teeth 7. Number and cross section of the teeth of successive rotor rows 17 vary in the same manner as the number and cross-section of the teeth 7 of the stator rows. Within operational range of the stator ribs 8, the rows 17 are followed by ribs 18, carried by the rotor '14, and grooves or channels 19 between the ribs 18, extending in the main direction of material movement, the rotor ribs 13 cooperating with the stator ribs 8. Opposite the rows 10 of stator teeth, the rotor 14 bears rows '20 of rotor teeth interrneshing with the rows 19 to cooperate with the latter in a shearing action. Number and cross section of the vibrator teeth of successive rows 26 vary in the same manner as the number and cross section of the teeth of the stator rows 10. The discharge of the treated material is promoted by pump vanes 23 provided on the rotor 14 at the outlet 3.

The cooperating stator ribs 5 and rotor ribs 15 and the cooperating stator ribs 8 and rotor ribs 18 form between them respective conical annular gaps 21 or 22. The optimum width of these gaps depends on the kind of the material and on the treatment desired and is adjustable by axial adjustment of the position of rotor 14. When the width of the annular gap is adjusted, the flanks and the shearing edges of the intermeshing elements 7, 17 and 10, 20 are axially adjusted relatively to one another so that the intensity of the shearing action can be altered or shearing effects completely avoided.

When one or more stator tooth rows are omitted and the adjacent rotor-teeth are extended into the space of the omitted stator-teeth, pump rings are formed by the longer rotor-teeth which increase the pumping effect. They may be helicoidally curved or inclined with regard to generating lines.

The material or stock conveyed e.-g. by a pump into the apparatus through the inlet 2 comes at first into the grooves or channels 6 and 16 and into the gap 21. Due to the rotation of the rotor '14 the stock in the rotor grooves 16 is thrown into the stator grooves 6 so that the grooves 16 are continuously emptied at their fore end. In this way a suction effect occurs at the inlet to the rotor 14 so that under certain circumstances pumping of the stock by special means into the apparatus through the inlet may be dispensed with. Owing to the centrifugal effect of the rotor 14 the grooves or channels 6 are filled up with material beyond their capacity, so that the ma terial in the gap 21 is sheared off or peeled off by the edges of the rotor-ribs 15. However, the main effect of the first groove stage 5, 15 on the material is compression, which makes for a relatively quiet and non-destruclive preliminary treatment of the material and, due to the conicity of the inner casing wall, promotes movement of the material in the main direction, i.e., along the inner wall towards the rows of teeth 7, 17. The continuous stream of material in the grooves 6 and the gap 21 is suddenly stopped and sheared off at the end of the ribs by the first row 17 of rotor teeth. Now, the stock is subjected to intensive treatment in and between the teeth rows, 7, 17 by repetitive action at high frequency (shearing, crushing, grinding, queezing, smashing, internal friction, skin friction, pressure differences, kinematically produced impulses). Since the diameter and the number of teeth increase from the first to the last teeth row, the frequency of treatment also rises. Depending on the number of teeth and the speed of rotation, the frequency may reach ultrasonic values if desired, and cavitation may occur already in the teeth 7, 17 After leaving the teeth 7, 17 the material enters the second rib group 8, 18 where similar effects occur as in the first rib group 5, -1'5 with the difference that, due to the larger diameter, these effects are of higher intensity. In this stage, the turbulence of the material is reduced and there is some shearing, but the ribs 8, 18 mainly provide pressure for bringing the material to the second group of rows of teeth 10, 20 where similar phenomena occur as in the first group but at a higher intensity and at a higher frequency due to the larger dimeter. After leaving the teeth 10, 20 the material or stock enters the space containing the pump vanes 23, where it is expanded or released. From said space it flows under the action of the pump vanes 23, through the outlet 3, whereupon it may be returned to the apparatus through the inlet 2 or through an intermediate connection to the annular gap, e.g. through a connect-ion on the level of the grooves 8, 18.

The apparatus described with reference to FIG. 5 is especially well suited for treating very delicate substances, such as, for instance, for disintegrating and refining cellulose (e.g. old waste paper) or similar raw materials with interconnected fibres in a single operation and in an economical manner without damaging the fibers. In the first of the four connecting working stages 5, 15; 7, 17;

8, 18 and 10, 20 the stock is subjected to kinematic effects F of low frequency which may decompose the stock into smaller fibre bundles or shives, in the second stage 7, 17 the frequency is higher. In the third stage 8, 18 a careful intermediate treatment is applied, eg a careful further loosening of the fibre structure and an acceleration of the main movement of the stock which was slowed down in the stage 7, 17, and in the fourth stage the frequency is highest for final treatment to produce, for instance, a high grade pulp. The number, kind and sequence of the successive stages operating at different frequencies depends on the properties of the material or stock, e.g., on its hardness, viscosity, ripeness, on the sensitivity of the fibres or on the degree of adhesion between the fibres.

The embodiment illustrated in FIGS. 6 and 7 differs from the example of FIG. 5 in that rib groups on the casing 1 and on the rotor 14 are omitted and only groups of rows of teeth are provided. Therefore, the material or stock is subjected already at the entry into the rotor 14 to high frequency effects of the kind described with reference to FIG. 8. The frequency increases steadily from the inlet to the outlet due to the increasing diameter of the conical two-part casing 1 and the conical part 24 of the rotor 14 and due to the increase in the number of teeth from row to row. The embodiment of FIGS. 6 and 7 is further distinguished from the apparatus of FIG. 5 in that the conical part 24 of the rotor 14 is followed by another conical part 25 with greater apex angle than part 24. The part 25 is likewise equipped with rows 26 of teeth cooperating in a shearing action with rows 27 of teeth of a conical casing part 28 corresponding to part 25. The rotor part 25 is followed by a further conical rotor part 29 whose apex angle is smaller than that of the part 25 and approximately equal to the apex angle of the part 24. Also the rotor part 29 is equipped with rows 30 of teeth intermeshing for a shearing action with rows 31 of teeth of a casing part 32 corresponding to rotor part 29. As best seen in FIG. 7, the rotor teeth 17 conform in shape and size to the interstices between the stator teeth 7, and vice versa as discussed hereinbefore with reference to FIG. 2.

The stock or material entering the apparatus through the intake 2 under the action of a pump (not shown) arrives at first between the rows of teeth 7 and 17 and is subjected to the same effects at increasing frequency as described in connection with the group 7, 17 of teeth shown in FIG. 5. To further the advance of the stock in the main moving direction, certain stator teeth rows 7 may be omitted and rotor pump rings substituted therefor, as has been described with reference to FIG. 5. Also in this embodiment, the teeth and/ or pump rings may be given the different shapes explained in connection with FIG. 5 and the annular gap of the first and third stages may, if desired, be cylindrical. When the material enters the spaces in and between the rows of teeth 26 and 27, it is subjected to a more intense pumping effect than before, due to the greater apex angle of the parts 25 and 28. At the transition point from the part 24 to the part 25 and in the entire range of the group of rows 26, 27 more intense cavitation occurs than in the group of rows 7, 17 because the material leaving the group 7, 17 cannot keep up with the material which is very considerably accelerated in the group 26, 27. Therefore, while in the group 7, 17 the material or stock is in a high pressure Zone it reaches a low pressure zone in the group 26, 27. During the transition from the group of rows 26, 27 to the group of teeth rows 30, 31 the reverse phenomenon occurs owing to the smaller apex angle of the parts 29, 32, i.e., the stock is subjected to high pressure in the group 30, 31 and is expanded or released on leaving the same. Depending on the structure of the stock and the aim of the treatment further stages disposed at an angle to one another may be added to the stage 29, 32. In the apparatus shown in FIG. 6 the material does not only undergo changes of pressure between the teeth of the rows but is also subjected to changes of pressure from stage to stage. Pump rings of the kind described with reference to FIG. 5 may also be provided on the parts 25 and 29. Pump vanes 23 are provided on the rotor 14 for facilitating the removal of the treated material from the outlet 3.

The afore-described apparatus of the invention may be modified by staggered stages such as the stages 25 and 29 of FIG. 6 and/ or other kinds of stages added to the apparatus shown in FIG. 5.

In the example of FIG. 8, the apparatus of the inven tion has a shaft 44 journaled in a bearing 101 of the cover of a container 86 and is suspended with the outlet towards the top on the cover of the container 86 by means of a bracket 84. A suction pipe 85 is connected to the inlet of the apparatus and extends down into the lower part of the container 86. The stock is drawn from the bottom of the container 86 through the suction pipe 85 and is discharged in a finely dispersed state at the outlet into the container space above the stock. The illustrated arrangement permits simultaneous treatment with gas or an aeration of the stock which is discharged from the apparatus into the upper empty container space. Air or another gas is fed into the container 86 through the conduit 87. If the treated stock in the container foams or contains finely distributed gas, it may also be degassed because the fine droplets are thrown from the apparatus against the wall of the container 86. A considerable separation of the gas from the stock takes place in the apparatus itself due to the different specific gravities of stock and gas. The small gas bubbles remaining in the stock are freed by their impact against the container wall so that the heavier stock drops towards the bottom and the gas escapes through the conduit 88.

FIG. 9 illustrates a spray drying installation. The apparatus according to the invention is flanged to the inside of the upper front face of a container 92 with its inlet towards the top and with its outlet towards the bottom. The shaft 44 of the apparatus is coupled with a motor 93 mounted above the container. The material or stock to be treated is fed to the apparatus through conduits 95 controlled by slides or valves 94. A feed conduit 96 for warm and dry air passes through the bottom of the container 92 and terminates in a distributor nozzle 97 through which the air enters the container. The container bottom has an outlet 98 and a conveyor 99 above it. The stock supplied to the apparatus through one or all of the conduits 95 is sprayed or atomised. The finely sprayed stock falls downwards in the form of droplets and while falling, can be dried by warm and dry air blown in through the conduit 96, so that the dry material accumulates in flaky condition on the container bottom wherefrom it is removed through the outlet 98 by the conveyor 99.

The apparatus proper the shaft of which may be driven from either end may be inserted in pipe lines, casings, machine units, e.g. in spray apparatus, in hopper mills, in continuously working extraction plants, in centrifuges, in silos, in pressure or vacuum boilers, in refining or reaction plants, furnaces etc.

The stator may be stationary, but it may also be driven in the same or opposite direction as the rotor. Therefore, the term stator in this description is to be understood broadly.

Several rotor-stator systems may be arranged on the same shaft.

The saponification of oils and fats with aqueous solutions of alkalis can be performed in the apparatus at great speed, high efiiciency and with excellent product homogeneity in a small fraction of the time necessary with known methods. Processes conventionally performed under pressure are capable of much quicker and more economical operation without pressure and heat in the apparatus of the invention. The method and apparatus according to the invention may be used for any physical or chemical transformation. The apparatus of the invention permits the manufacture of a homogeneous kaolin suspension as a filler or ceramic slip having a particle size of the order of magnitude of a micron, the production of cellulose from chemical wood chips up to complete fibre separation, the production of cellulose from unsorted old waste paper, the esterifying of a resin and the production of an artificial phenol formaldehyde resin, the homogenizing of heterogeneous mixtures, the flocculation and production of stable suspensions of extremely finely distributed silicic acid (eg as a filler stabilizer), the production of an emulsion from talcum, Vaseline and lanoline, the preparation of a suspension of mineral oil distillate, methyl alcohol, tannin and graphite etc.

The dimensions of the different stages of the apparatus according to the invention, such as their length, diameters and their conical or cylindrical shape may be chosen in accordance with requirements.

What I claim is:

1. In an apparatus for mechanical treatment of material, in combination, two bodies having respective face portions oppositely arranged to define a gap therebetween; means for rotating one of said bodies relative to the other about an axis, said face portions and said gap being substantially coaxially arranged relative to said axis; a separator ring mounted on said one body and provided with perforations, said perforations communicating with said gap; means for admitting a material to said gap for movement therethrough in a predetermined direction from an inlet to an outlet of said gap; and a plurality of spaced projeections on each of said face portions extending into said gap for cooperation with the projections of the other face portion, the projections on each of said face portions being arranged in a plurality of coaxial rows transverse to said predetermined direction, the projections in each of said rows being of substantially uniform shape and defining substantially uniform interstices therebetween, rows of projections of one of said face portions being alternatingly juxtaposed in said direction with rows of projections of the other face portion, the cross section of each projection taken transversely of said direction substantially conforming to the corresponding cross section of the interstices in a juxtaposed row of projections.

2. In an apparatus for mechanical treatment of material, in combination, two bodies having respective face portions oppositely arranged to define a gap therebetween; means for rotating one of said bodies relative to the other about an axis, said face portions and said gap being substantially coaxially arranged relative to said axis; a collector channel adjacent said gap, said collector channel having a permeable wall; means for admitting a material to said gap for movement therethrough in a predetermined direction from an inlet to an outlet of said gap; and a plurality of spaced projections on each of said face portions extending into said gap for cooperation with the projections of the other face portion, the projections on each of said face portions being arranged in a plurality of coaxial rows transverse to said predetermined direction, the projections in each of said rows being of substantially uniform shape and defining substantially uniform interstices therebetween, rows of projections of one of said face portions being alternatingly juxtaposed in said direction with rows of projections of the other face portion, the cross section of each projection taken transversely of said direction substantially conforming to the corresponding cross section of the interstices in a juxtaposed row of projections.

3. In an apparatus for mechanical treatment of material, in combination, a container; two bodies suspended in said container and having respective face portions oppositely arranged to define a gap therebetween; means for rotating one of said bodies relative to the other about an axis, said face portions and said gap being substantially coaxially arranged relative to said axis; means for admitting a material to said gap for movement therethrough in a predetermined direction from an inlet to an outlet of said gap, said outlet being directed toward the bottom of said container; a feed conduit for dry air leading from below to the container for spray drying the material discharged from said outlet and falling down towards said container bottom; and a plurality of spaced projections on each of said face portions extending into said gap for cooperation with the projections of the other face portion the projections on each of said face portions being arranged in a plurality of coaxial rows transverse of said predetermined direction, the projections in each of said rows being of substantially uniform shape and defining substantially uniform interstices therebetween, rows of projections of one of said face portions being alternatingly juxtaposed in said direction with rows of projections of the other face portion, the cross section of each projection taken transversely of said direc tion substantially conforming to the corresponding cross section of the interstices in a juxtaposed row of pro jections.

4. In an apparatus for mechanical treatment of material, in combination, two bodies having respective face portions oppositely arranged to define a gap therebetween; means for rotating one of said bodies relative to the other about an axis, said face portions and said gap being substantially coaxially arranged relative to said axis; means for admitting a material to said gap for movement therethrough in a predetermined direction from an inlet to an outlet of said gap; and a plurality of spaced projections on each of said face portions extending into said gap for cooperation with the projections of the other face portion the projections on each of said face portions being arranged in a plurality of coaxial rows transverse to said predetermined direction, the projections in each of said rows being of substantially uniform shape and defining substantially uniform interstices therebetween, rows of projections of one of said face portions being alternatingly juxtaposed in said direction with rows of projections of the other face portion, the cross section of each projection taken transversely of said direction substantially conforming to the corresponding cross section of the interstices in a juxtaposed row of projections, at least a portion of the projections of said one body being elongated, the elongation extending in said predetermined direction, said elongated projections forming together a pump ring in the form of an annular row about said ax1s.

5. In an apparatus for mechanical treatment of mate rial, in combination, two bodies having respective face portions oppositely arranged to define a gap therebetween; means for rotating one of said bodies relative to the other about an axis, said face portions and said gap being substantially coaxially arranged relative to said axis; means for admitting a material to said gap for movement therethrough in a predetermined direction from an inlet to an outlet of said gap, said gap having three conical portions consecutively arranged in said predetermined direction of movement, the second consecutive conical portion having a larger apex angle than the first portion, and the third consecutive conical gap portion having a smaller apex angle than said second consecutive gap portion; and a plurality of spaced projections on each of said face portions extending into said gap for cooperation with the projections of the other face portion, the projections on each of said face portions being arranged in a plurality of coaxial rows transverse to said predetermined direction, the projections in each of said rows being of substantially uniform shape and defining substantially uniform interstices therebetween, rows of projections of one of said face portions being alternatingly juxtaposed in said direction with rows of projections of the other face portion, the cross section of each projection taken transversely of said direction substantially conforming to the corresponding cross section of the interstices in a juxtaposed row of projections.

6. In an apparatus for subjecting a stream of material to mechanical stresses, in combination:

(a) a first member;

(b) a second member;

(0) means for rotating said members relative to each other about an axis, said members defining an annular conical gap having two orifices axially spaced from each other for passage of said stream through said gap in a predetermined direction; and

(d) a plurality of circumferentially spaced projections on each of said members and extending from the respective member into said gap toward the other member for sequential spaced interengagement with the projections thereof during rotation of said members relative to each other,

(e) said projections being arranged in a plurality of axially spaced coaxial rows about said axis,

(f) the projections in each of said rows being of sub stantially uniform. shape and defining substantially .uniform interstices therebetween,

(g) a row of projections on each of said members being alter-natingly interposed in said predetermined direction between two rows of projections on the other member,

(h) the cross section of each projection of said two rows in a radial plane substantially conforming to the corresponding cross section of the interstices in said one row of projections.

7. In an apparatus for mechanical treatment of material, in combination:

(a) two bodies having respective face portions oppositely arranged to define a gap therebet-ween;

(b) means for rotating one of said bodies relative to the other about an axis, said face portions and said gap being substantially coaxially arranged relative to said axis;

(0) means for admitting a material to said gap for movement therethrough in a predetermined direction from an inlet to an outlet of said gap; and

(d) a plurality of spaced projections on each of said face portions extending into said gap for cooperation with the projections of the other face portion, the projections on each of said face portions being arranged in a plurality of coaxial rows transverse to said predetermined direction,

(e) the projections in each of said rows being of substantially uniform shape and defining substantially uni-form interstices therebetween,

(f) a row of projections of each of said face portions being interposed in said direction between two rows of projections of the other face portions,

( g) the cross section of each projection of said two rows taken transversely of said direction substantially conforming to the corresponding cross section of the interstices of said one row of projections.

8. In an apparatus as claimed in claim 7, said gap being conical and annular, the width of said gap transversely of said direction of movement of said material decreasing in a direction from said inlet toward said outlet.

9. An apparatus as claimed in claim 7, the gap defined by said face portions extending along a plane.

10. An apparatus as claimed in claim 7, including a container, a suction pipe having an orifice in the lower portion of said container and another orifice communicating with said gap for admitting said material from said container to said gap, and means for discharging said material from said gap into a free space of the container above said lower portion.

11. An apparatus as claimed in claim 7, said gap having two conical portions consecutively arranged in said predetermined direct-ion of movement, the second consecutive conical portion having a larger apex angle than the first portion.

(References on following page) 11 References Cited in the file of this patent UNITED STATES PATENTS Wagg June 28, 1904 Hance Nov. 11, 1913 Head Apr. 10, 1923 5 Black Aug. 30, 1932 Harnmes Aug. 27, 1935 Ambrose Mar. 31, 1942 Brant Sept. 7, 1943 10 Bried Mar. 21, 1944 12 Brant Aug. 16, 1949 Scherer Dec. 30, 19 52 White Nov. 16, 1954 Armstrong Sept. 6, 1955 Schneider Mar. 20, 1956 Minmbeng Nov. 20, 1956 Reerink Nov. 11, 1958 Wu'llems Apr. 14, 1959 FOREIGN PATENTS Germany Oct. 16, 1934 

7. IN AN APPARATUS FOR MECHANICAL TREATMENT OF MATERIAL, IN COMBINATION: (A) TWO BODIES HAVING RESPECTIVE FACE PORTIONS OPPOSITELY ARRANGED TO DEFINE A GAP THEREBETWEEN; (B) MEANS FOR ROTATING ONE OF SAID BODIES RELATIVE TO THE OTHER ABOUT AN AXIS, SAID FACE PORTIONS AND SAID GAP BEING SUBSTANTIALLY COAXIALLY ARRANGED RELATIVE TO SAID AXIS; (C) MEANS FOR ADMITTING A MATERIAL TO SAID GAP FOR MOVEMENT THERETHROUGH IN A PREDETERMINED DIRECTION FROM AN INLET TO AN OUTLET OF SAID GAP; AND (D) A PLURALITY OF SPACED PROJECTIONS ON EACH OF SAID FACE PORTIONS EXTENDING INTO SAID GAP FOR COOPERATION WITH THE PROJECTIONS OF THE OTHER FACE PORTION, THE PROJECTIONS ON EACH OF SAID FACE PORTIONS BEING ARRANGED IN A PLURALITY OF COAXIAL ROWS TRANSVERSE TO SAID PREDETERMINED DIRECTION, (E) THE PROJECTIONS IN EACH OF SAID ROWS BEING OF SUBSTANTIALLY UNIFORM SHAPE AND DEFINING SUBSTANTIALLY UNIFORM INTERSTICES THEREBETWEEN, (F) A ROW OF PROJECTIONS OF EACH OF SAID FACE PORTIONS BEING INTERPOSED IN SAID DIRECTION BETWEEN TWO ROWS OF PROJECTIONS OF THE OTHER FACE PORTIONS, (G) THE CROSS SECTION OF EACH PROJECTION OF SAID TWO ROWS TAKEN TRASVERSELY OF SAID DIRECTION SUBSTANTIALLY CONFORMING TO THE CORRESPONDING CROSS SECTION OF THE INTERSTICES OF SAID ONE ROW OF PROJECTIONS. 